It is kniwn to those skilled in the art that "fixed" or "mechanical" orthodontic therapies provide, essentially, for the application of a force, having predetermined intensity and direction, on each tooth of the arches under corrective treatment, so as to determine their slow and gradual displacement within respective alveoli until they reach a position that would be judged optimal as a whole by an orthodontist.
In case of intraoral devices with vestibular action, the corrective forces are applicable, for example, by means of a plurality of attachments able to be fixed to the vestibular and lingual versants of the teeth and interconnected by elastic members such as preformed arches and springs. Said elastic members are intended to generate the forces--of reactive nature, owing to the deformation they are subjected to upon use--to be applied to the teeth in correspondence of the attachements location.
The orthopedic therapies for the correction of dento-facial disfunctions make it possible, by modulating the forces applied on the teeth so as to transmit the same forces more deeply, to intervene on the osseous structure so as to change its arrangement to a more or less extent depending on the gravity and nature of the intervention, that is, of the malformation to be treated. In the case, for example, of orthopedic procedures for the rapid expansion of the palate, apparatus are used able to open the mid-palatine suture directly and the adjacent sutures indirectly, for the correction of superior maxilla's deficit. These apparatus comprise, essentially, an expansion screw, also said "disjunctor", having side arms connected to latero-posterior teeth of the superior arch by bands of metallic material, such as the LEONE screw model A 620 or the screws disclosed in U.S. Pat. Nos. 3,835,540 and 4,571,177.
The upper maxilla is fixed and solid to the rest of the skull. The mandibula is the only movable bone of the skull and, because of its structure, is unsuitable for orthopedics as conventionally applied to the maxilla. Accordingly, the orthopedics of the mandibula is carried out by exploiting the mobility of the latter through some conditionings of its position and, therefore, of its function. This has such biological effects on the mandibula and its relevant functions, as those caused by the disjunctor on the superior maxilla. This is why reference is made to "functional" orthopedics whenever use has been made in the oral cavity of removable and irremovable apparatus generally made of acrilic resins and able to condition the mandibular position, usually under protrusion. In fact, the structural advancement of the mandibula is usually requested in cases of second-class malocclusions in which, typically, one resorts to orthopedic therapy with movable apparatus.
Conventional corrective therapies, both of orthodontic and orthopedic kind, make use of apparatus, for example of the type above described, especially constructed for application thereof in different times, that is, with separate intervention procedures and such, anyway, that the therapeutic times add to one another when the need arises for both orthopedic and orthodontic intervention, which brings about an excessive and prolonged discomfort also of psycological character for the patient.